[Alt-photo] Re: lump gum

[Henry Rattle]

I get lump gum from Cornelissen in London, and make up (from memory, I'm away from home) 70 grams in 300 ml water, which looks about the same concentration as Kees is using. Leave in a jar with a lid so you can shake it up regularly (otherwise it turns into a sticky mass that takes forever to dissolve) and it dissolves in about 24 hours. Filter out the twigs, insect wings etc (I use two layers of the thin domestic cleaning cloths that in UK are called J-cloths) and the result is a lovely clear gum to which I add a little preservative-I use a few drops of formalin because I have it, but others use thymol or other preservatives. The made-up gum lasts very well - I've used it three years on with good results.

Best wishes

Henry

Sent from my iPad

> On Oct 19, 2013, at 17:01, Kees Brandenburg <workshops at polychrome.nl> wrote:
> 
> Hi Laura,
> 
> Most of the time I am using gum in lumps. I disolve these to a 26% solution (by weight) by taking 260 grams and add water to a total of 1000gr. I allways fold the lumps in a peace of cheesecloth, bind it together and hang it in the water in a jar. Time does the rest. Squeeze it after 24 hours (or more). The gritty stuf stays in the cloth!
> 
> Powdered gum can also be found at kremerpigmente.com. I always get a much clearer gum with  the lump/cheescloth method!
> 
> kees
> 
> 
> 
>> On 19 okt. 2013, at 14:58, Laura V <laura at lavatop.com> wrote:
>> 
>> Previously, I had used pre-mixed gum arabic and also the powdered version which I mixed myself, but then I ran out. The pre-mixed is so expensive to ship, and I couldn't find the powdered stuff online, so I ordered lump gum which I've never used. I can't find any instructions for mixing it, but finally just put some in a plastic container with roughly an equal amount of water. A day later and some of the lumps have melted, but the bigger ones are still there and it's kind of gritty and hairy looking. I suppose I'll just filter out the lumps and gritty stuff - but was I supposed to do anything differently such as heat the water?
>> 
>> I was really surprised at how large some of the lumps were - I was expecting something where the lumps were more evenly sized. Has anyone used this stuff? Here's an image: http://lauraval.com/gumlumps.jpg That's a 2-liter sized ice-cream container so those lumps are BIG!
> 
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